As a conventional metallic hollow golf club head in which a face plate is welded, a golf club head shown in FIG. 8 has been known. In this golf club head, a substantially rectangular opening 20 is formed in a face part 2 of a metallic head body 1 having a cavity 10 therein, and a face plate 30 having a shape matching the opening 20 is laser welded to a receiving part 2b formed at the periphery of the opening 20. The head body 1 includes a crown part 3, a sole part 4, and a hosel 5 in addition to the face part 2, and has a toe 6 and a heel 7. In this conventional example, the welding strength is improved, and therefore damage is less liable to occur (refer to JP 2004-65853 A1).
Also, as a golf club head in which the whole of the face part is a member separate from the head body and this face part is welded to the head body, there has been known a golf club head in which the face part is deflected when the ball is hit by decreasing the thickness of the face part, thereby increasing carry. By being influenced by the shape of the head body, such a face part is formed so that the length in the right and left direction (the toe-heel direction) is greater than the length in the up and down direction (the top-sole direction). Therefore, the defection of the face part when the ball is hit is longer in the right and left direction than in the up and down direction, and the slope toward the center position at which the deflection is greatest is gentler in the right and left direction than in the up and down direction of face. For this reason, the ball is not compressed by a shock when the ball is hit while the ball cross section perpendicular to the hit direction (the ball compressing direction) is maintained in a circular shape. Uneven compression causes distortion of the circular cross-sectional shape, which makes it difficult to control the direction that the ball flies.
As a golf club head for solving the above problem, there has been known a golf club head in which an opening having almost the same lengths in the up and down direction and the right and left direction is formed in the face part, and a face plate having the same shape as that of the opening is welded to the opening, by which the occurrence of anisotropy is prevented, and the rebounding force at the hit time is increased by compressing a ball into a uniform shape (refer to JP 2003-265656 A1).